If you're flying from an airport in London, you can now pack your carry-on bag with a full-size sunscreen, a liter of diet soda and a laptop without unpacking a thing. Want to bring hair cream or body lotion? No problem. And let's not forget a full bottle of water — or whiskey — for the trip.

But you can't do that in the U.S. thanks to the ritual known as the 100ml liquid rule. It's been part of our travel lives for nearly 20 years. You can't fly to or from anywhere in the U.S. with any liquids above 100 ml.

But earlier this year, officials at London's Heathrow announced that the airport had finished a £1 billion scanner upgrade, and that the 100ml limit was lifted across all four terminals: T2, T3, T4 and T5. Now, Heathrow passengers they can keep liquids in their cabin bags, carry individual containers of up to 2 liters each, and leave large electronics like laptops and tablets inside the bag.

The shift at Heathrow actually came late. It was one of the last major UK airports to make the change, more than seven years (that's right — seven years) after the next-generation technology was first announced.